Method for user equipment transmitting service preference information in wireless communication system and apparatus for same

ABSTRACT

The present invention relates to a method for a user equipment to transmit/receive a signal in a wireless communication system, and more specifically, comprises the following steps: setting a priority between a multimedia broadcast multicast service (MBMS) and a unicast service; transmitting the priority which is set to a network; transmitting a measurement report on a target node to the network; and receiving from the network a handover command which is determined based on the priority and the measurement report.

TECHNICAL FIELD

The present invention relates to a wireless communication system, andmore particularly, to a method and apparatus for transmitting servicepreference information from a user equipment (UE) in a wirelesscommunication system.

BACKGROUND ART

As an example of a wireless communication system to which the presentinvention is applicable, a 3^(rd) generation partnership project (3GPP)long term evolution (LTE) communication system will be schematicallydescribed.

FIG. 1 is a schematic diagram showing a network structure of an evolveduniversal mobile telecommunications system (E-UMTS) as an example of awireless communication system. The E-UMTS is an evolved form of thelegacy UMTS and has been standardized in the 3GPP. In general, theE-UMTS is also called an LTE system. For details of the technicalspecification of the UMTS and the E-UMTS, refer to Release 7 and Release8 of “3^(rd) Generation Partnership Project; Technical SpecificationGroup Radio Access Network”.

Referring to FIG. 1, the E-UMTS includes a user equipment (UE), anevolved node B (eNode B or eNB), and an access gateway (AG) which islocated at an end of an evolved UMTS terrestrial radio access network(E-UTRAN) and connected to an external network. The eNB maysimultaneously transmit multiple data streams for a broadcast service, amulticast service and/or a unicast service.

One or more cells may exist per eNB. The cell is set to operate in oneof bandwidths such as 1.25, 2.5, 5, 10, 15, and 20 MHz and provides adownlink (DL) or uplink (UL) transmission service to a plurality of UEsin the bandwidth. Different cells may be set to provide differentbandwidths. The eNB controls data transmission or reception to and froma plurality of UEs. The eNB transmits DL scheduling information of DLdata to a corresponding UE so as to inform the UE of a time/frequencydomain in which the DL data is supposed to be transmitted, coding, adata size, and hybrid automatic repeat and request (HARQ)-relatedinformation. In addition, the eNB transmits UL scheduling information ofUL data to a corresponding UE so as to inform the UE of a time/frequencydomain which may be used by the UE, coding, a data size, andHARQ-related information. An interface for transmitting user traffic orcontrol traffic may be used between eNBs. A core network (CN) mayinclude the AG and a network node or the like for user registration ofUEs. The AG manages the mobility of a UE on a tracking area (TA) basis.One TA includes a plurality of cells.

Although wireless communication technology has been developed to LTEbased on wideband code division multiple access (WCDMA), the demands andexpectations of users and service providers are on the rise. Inaddition, considering other radio access technologies under development,new technological evolution is required to secure high competitivenessin the future. Decrease in cost per bit, increase in serviceavailability, flexible use of frequency bands, a simplified structure,an open interface, appropriate power consumption of UEs, and the likeare required.

DISCLOSURE Technical Problem

An object of the present invention devised to solve the problem lies ina method of and apparatus for transmitting service preferenceinformation from a user equipment (UE) in a wireless communicationsystem.

Technical Solution

The object of the present invention can be achieved by providing amethod for transmitting and receiving a signal at a user equipment (UE)in a wireless communication system, the method including setting apriority between a multimedia broadcast multicast service (MBMS) and aunicast service, transmitting the priority to a network, transmitting ameasurement report on a target node to the network, and receiving ahandover command determined based on the priority and the measurementreport from the network.

In another aspect of the present invention, provided herein is a methodfor transmitting and receiving a signal between a network and a userequipment (UE) in a wireless communication system, the method includingreceiving a priority between a multimedia broadcast multicast service(MBMS) and a unicast service, receiving a measurement report on a targetnode from the UE, determining whether handover to the target node isperformed based on the priority and the measurement report, andtransmitting a handover command to the target node to the UE.Preferably, the method may further include transmitting a handoverrequest message to the target node, and receiving a handover requestresponse message from the target node, wherein the handover requestmessage includes the priority.

The measurement report may include information indicating whether the UEcurrently receives the MBMS provided at a frequency of the target nodeor the UE is interested in reception of the MBMS provided at thefrequency of the target node. In addition, the priority may be includedin a handover request message transmitted from a serving node to thetarget node. Furthermore, the priority may correspond to userpreference.

More preferably, the serving node may be a serving cell and the targetnode may be a target cell.

The unicast service may include at least one of a closed subscribergroup (CSG) service, a voice service, a UE dedicated service, and avirtual private network (VPN) service.

Advantageous Effects

According to the embodiments of the present invention, a network mayeffectively provide a multimedia broadcast multicast service (MBMS) to auser equipment (UE). In detail, the UE may transmit service preferenceinformation to the network such that the network may handover the UE toa cell that can provide the MBMS, and thus, the UE may effectivelyreceive a preferred service.

The effects of the present invention are not limited to theabove-described effects and other effects which are not described hereinwill become apparent to those skilled in the art from the followingdescription.

DESCRIPTION OF DRAWINGS

FIG. 1 is a diagram showing a network structure of an Evolved UniversalMobile Telecommunications System (E-UMTS) as an example of a wirelesscommunication system.

FIG. 2 is a diagram conceptually showing a network structure of anevolved universal terrestrial radio access network (E-UTRAN).

FIG. 3 is a diagram showing a control plane and a user plane of a radiointerface protocol between a UE and an E-UTRAN based on a 3^(rd)generation partnership project (3GPP) radio access network standard.

FIG. 4 is a diagram showing physical channels used in a 3GPP system anda general signal transmission method using the same.

FIG. 5 is a diagram showing the structure of a radio frame used in aLong Term Evolution (LTE) system.

FIG. 6 is a diagram showing a general transmission and reception methodusing a paging message.

FIG. 7 is a diagram showing a transmission method of multimediabroadcast multicast service control channel (MCCH) information.

FIG. 8 is a diagram of a wireless communication system including a homeeNB (HeNB).

FIG. 9 is a diagram of a handover process based on service preference,according to an embodiment of the present invention.

FIG. 10 is a block diagram of a communication apparatus according to anembodiment of the present invention.

BEST MODE

The configuration, operation and other features of the present inventionwill be understood by the embodiments of the present invention describedwith reference to the accompanying drawings. The following embodimentsare examples of applying the technical features of the present inventionto a 3rd generation partnership project (3GPP) system.

Although the embodiments of the present invention are described using along term evolution (LTE) system and a LTE-advanced (LTE-A) system inthe present specification, they are purely exemplary. Therefore, theembodiments of the present invention are applicable to any othercommunication system corresponding to the above definition. In addition,although the embodiments of the present invention are described based ona frequency division duplex (FDD) scheme in the present specification,the embodiments of the present invention may be easily modified andapplied to a half-duplex FDD (H-FDD) scheme or a time division duplex(TDD) scheme.

FIG. 2 is a diagram conceptually showing a network structure of anevolved universal terrestrial radio access network (E-UTRAN). An E-UTRANsystem is an evolved form of a legacy UTRAN system. The E-UTRAN includescells (eNB) which are connected to each other via an X2 interface. Acell is connected to a user equipment (UE) via a radio interface and toan evolved packet core (EPC) via an S1 interface.

The EPC includes a mobility management entity (MME), a serving-gateway(S-GW), and a packet data network-gateway (PDN-GW). The MME hasinformation about connections and capabilities of UEs, mainly for use inmanaging the mobility of the UEs. The S-GW is a gateway having theE-UTRAN as an end point, and the PDN-GW is a gateway having a packetdata network (PDN) as an end point.

FIG. 3 is a diagram showing a control plane and a user plane of a radiointerface protocol between a UE and an E-UTRAN based on a 3GPP radioaccess network standard. The control plane refers to a path used fortransmitting control messages used for managing a call between the UEand the E-UTRAN. The user plane refers to a path used for transmittingdata generated in an application layer, e.g., voice data or Internetpacket data.

A physical (PHY) layer of a first layer provides an information transferservice to a higher layer using a physical channel. The PHY layer isconnected to a medium access control (MAC) layer located on the higherlayer via a transport channel. Data is transported between the MAC layerand the PHY layer via the transport channel. Data is transported betweena physical layer of a transmitting side and a physical layer of areceiving side via physical channels. The physical channels use time andfrequency as radio resources. In detail, the physical channel ismodulated using an orthogonal frequency division multiple access (OFDMA)scheme in downlink and is modulated using a single carrier frequencydivision multiple access (SC-FDMA) scheme in uplink.

The MAC layer of a second layer provides a service to a radio linkcontrol (RLC) layer of a higher layer via a logical channel. The RLClayer of the second layer supports reliable data transmission. Afunction of the RLC layer may be implemented by a functional block ofthe MAC layer. A packet data convergence protocol (PDCP) layer of thesecond layer performs a header compression function to reduceunnecessary control information for efficient transmission of anInternet protocol (IP) packet such as an IP version 4 (IPv4) packet oran IP version 6 (IPv6) packet in a radio interface having a relativelysmall bandwidth.

A radio resource control (RRC) layer located at the bottom of a thirdlayer is defined only in the control plane. The RRC layer controlslogical channels, transport channels, and physical channels in relationto configuration, re-configuration, and release of radio bearers (RBs).An RB refers to a service that the second layer provides for datatransmission between the UE and the E-UTRAN. To this end, the RRC layerof the UE and the RRC layer of the E-UTRAN exchange RRC messages witheach other.

One cell of the eNB is set to operate in one of bandwidths such as 1.25,2.5, 5, 10, 15, and 20 MHz and provides a downlink or uplinktransmission service to a plurality of UEs in the bandwidth. Differentcells may be set to provide different bandwidths.

Downlink transport channels for transmission of data from the E-UTRAN tothe UE include a broadcast channel (BCH) for transmission of systeminformation, a paging channel (PCH) for transmission of paging messages,and a downlink shared channel (SCH) for transmission of user traffic orcontrol messages. Traffic or control messages of a downlink multicast orbroadcast service may be transmitted through the downlink SCH and mayalso be transmitted through a separate downlink multicast channel (MCH).

Uplink transport channels for transmission of data from the UE to theE-UTRAN include a random access channel (RACH) for transmission ofinitial control messages and an uplink SCH for transmission of usertraffic or control messages. Logical channels that are defined above thetransport channels and mapped to the transport channels include abroadcast control channel (BCCH), a paging control channel (PCCH), acommon control channel (CCCH), a multicast control channel (MCCH), and amulticast traffic channel (MTCH).

FIG. 4 is a diagram showing physical channels used in a 3GPP system anda general signal transmission method using the same.

When a UE is powered on or enters a new cell, the UE performs an initialcell search operation such as synchronization with an eNB (S401). Tothis end, the UE may receive a primary synchronization channel (P-SCH)and a secondary synchronization channel (S-SCH) from the eNB to performsynchronization with the eNB and acquire information such as a cell ID.Then, the UE may receive a physical broadcast channel from the eNB toacquire broadcast information in the cell. During the initial cellsearch operation, the UE may receive a downlink reference signal (DL RS)so as to confirm a downlink channel state.

After the initial cell search operation, the UE may receive a physicaldownlink control channel (PDCCH) and a physical downlink control channel(PDSCH) based on information included in the PDCCH to acquire moredetailed system information (S402).

When the UE initially accesses the eNB or has no radio resources forsignal transmission, the UE may perform a random access procedure (RACH)with respect to the eNB (steps S403 to S406). To this end, the UE maytransmit a specific sequence as a preamble through a physical randomaccess channel (PRACH) (S403) and receive a response message to thepreamble through the PDCCH and the PDSCH corresponding thereto (S404).In the case of contention-based RACH, the UE may further perform acontention resolution procedure.

After the above procedure, the UE may receive PDCCH/PDSCH from the eNB(S407) and may transmit a physical uplink shared channel(PUSCH)/physical uplink control channel (PUCCH) to the eNB (S408), whichis a general uplink/downlink signal transmission procedure.Particularly, the UE receives downlink control information (DCI) throughthe PDCCH. Here, the DCI includes control information such as resourceallocation information for the UE. Different DCI formats are definedaccording to different usages of DCI.

Control information transmitted from the UE to the eNB in uplink ortransmitted from the eNB to the UE in downlink includes adownlink/uplink acknowledge/negative acknowledge (ACK/NACK) signal, achannel quality indicator (CQI), a precoding matrix index (PMI), a rankindicator (RI), and the like. In the case of the 3GPP LTE system, the UEmay transmit the control information such as CQI/PMI/RI through thePUSCH and/or the PUCCH.

FIG. 5 is a diagram showing the structure of a radio frame used in anLTE system.

Referring to FIG. 5, the radio frame has a length of 10 ms (327200×Ts)and is divided into 10 subframes having the same size. Each of thesubframes has a length of 1 ms and includes two slots. Each of the slotshas a length of 0.5 ms (15360×Ts). Ts denotes a sampling time, and isrepresented by Ts=1/(15 kHz×2048)=3.2552×10⁻⁸ (about 33 ns). Each of theslots includes a plurality of OFDM symbols in a time domain and aplurality of Resource Blocks (RBs) in a frequency domain. In the LTEsystem, one RB includes 12 subcarriers×7 (or 6) OFDM symbols. Atransmission time interval (TTI) that is a unit time for transmission ofdata may be determined in units of one or more subframes. The structureof the radio frame is purely exemplary and thus the number of subframesincluded in the radio frame, the number of slots included in a subframe,or the number of OFDM symbols included in a slot may be changed invarious ways.

Hereinafter, an RRC state of a UE and an RRC connection method will bedescribed.

The RRC state indicates whether the RRC layer of the UE is logicallyconnected to the RRC layer of the E-UTRAN. When the RRC connection isestablished, the UE is in a RRC_CONNECTED state. Otherwise, the UE is ina RRC_IDLE state.

The E-UTRAN can effectively control UEs because it can check thepresence of RRC_CONNECTED UEs on a cell basis. On the other hand, theE-UTRAN cannot check the presence of RRC_IDLE UEs on a cell basis andthus a CN manages RRC_IDLE UEs on a TA basis. A TA is an area unitlarger than a cell. That is, in order to receive a service such as avoice service or a data service from a cell, the UE needs to transitionto the RRC_CONNECTED state.

In particular, when a user initially turns a UE on, the UE firstsearches for an appropriate cell and camps on the cell in the RRC_IDLEstate. The RRC_IDLE UE transitions to the RRC_CONNECTED state byperforming an RRC connection establishment procedure only when theRRC_IDLE UE needs to establish an RRC connection. For example, whenuplink data transmission is necessary due to call connection attempt ofa user or when a response message is transmitted in response to a pagingmessage received from the E-UTRAN, the RRC_IDLE UE needs to be RRCconnected to the E-UTRAN.

FIG. 6 is a diagram showing a general transmission and reception methodusing a paging message.

Referring to FIG. 6, the paging message includes a paging record havingpaging cause and UE identity. Upon receiving the paging message, the UEmay perform a discontinuous reception (DRX) operation in order to reducepower consumption.

In detail, a network configures a plurality of paging occasions (POs) inevery time cycle called a paging DRC cycle and a specific UE receivesonly a specific paging occasion and acquires a paging message. The UEdoes not receive a paging channel in paging occasions other than thespecific paging occasion and may be in a sleep state in order to reducepower consumption. One paging occasion corresponds to one TTI.

The eNB and the UE use a paging indicator (PI) as a specific valueindicating transmission of a paging message. The eNB may define aspecific identity (e.g., paging-radio network temporary identity(P-RNTI)) as the PI and inform the UE of paging informationtransmission. For example, the UE wakes up in every DRX cycle andreceives a subframe to determine the presence of a paging messagedirected thereto. In the presence of the P-RNTI on an L1/L2 controlchannel (a PDCCH) in the received subframe, the UE is aware that apaging message exists on a PDSCH of the subframe. When the pagingmessage includes an ID of the UE (e.g., an international mobilesubscriber identity (IMSI)), the UE receives a service by responding tothe eNB (e.g., establishing an RRC connection or receiving systeminformation).

System information will now be described. The system informationincludes essential information necessary to connect a UE to an eNB.Accordingly, the UE should receive all system information before beingconnected to the eNB and should always have new system information. TheeNB periodically transmits the system information because all UEslocated in a cell should know the system information.

The system information may be divided into a master information block(MIB), a scheduling block (SB), and a system information block (SIB).The MIB enables a UE to become aware of a physical configuration of acell, for example, a bandwidth. The SB indicates transmissioninformation of SIBs, for example, a transmission period. The SIB is aset of associated system information. For example, a specific SIBincludes only information about peripheral cells and another SIBincludes only information about an uplink radio channel used by a UE.

Hereinafter, a cell selection and cell reselection process will bedescribed.

When a UE is powered on, the UE needs to select a cell havingappropriate quality and to perform preparation procedures for receivinga service. An RRC_IDLE UE should always select appropriate quality andprepare to receive a service from the cell. For example, a UE which hasjust been turned on should select a cell having appropriate quality inorder to perform registration with a network. When an RRC_CONNECTED UEenters an RRC_IDLE state, the UE should select a cell on which the UEwill camp in the RRC_IDLE state. A process of, at a UE, selecting a cellsatisfying a specific condition in order to camp on the cell in aservice standby state such as an RRC_IDLE state is referred to as cellselection. Since the cell selection is performed in a state in which theUE does not determine a cell on which the UE camps in the RRC_IDLEstate, it is important to select a cell as fast as possible.Accordingly, a cell which provides radio signal quality equal to orgreater than a predetermined reference may be selected in the cellselection process of the UE, even if the cell does not provide the bestradio signal quality to the UE.

When the UE selects a cell satisfying a cell selection reference, the UEreceives information necessary for an operation of the RRC_IDLE UE inthe cell from the system information of the cell. The UE receives allinformation necessary for the operation of the RRC_IDLE UE and thenrequests a service from a network or awaits reception of a service fromthe network in a RRC_IDLE state.

After the UE selects a certain cell in the cell selection process, theintensity or quality of a signal between the UE and the eNB may bechanged due to mobility of the UE or wireless environment change.Accordingly, when the quality of the selected cell deteriorates, the UEmay select another cell which provides better quality. When the cell isreselected, a cell which provides better signal quality than a currentlyselected cell is generally selected. Such a process is referred to ascell reselection. The cell reselection process is performed in order toselect a cell which provides the best quality to the UE from theviewpoint of the quality of the radio signal. In addition to the qualityof the radio signal, the network may set a priority per frequency andinform the UE of the priority. The UE which receives the prioritypreferentially takes the priority into consideration, rather than theradio signal quality.

Hereinafter, a multimedia broadcast multicast service (MBMS) will bedescribed. The MBMS refers to a kind of broadcast/multicast service andsimultaneously transmits multimedia data packets to a plurality of UEs.The terms ‘broadcast/multicast service’ and ‘MBMS’ used in the presentspecification may be replaced with terms ‘point-to-multipoint service’and ‘multicast and broadcast service (MBS)’. With regard to the MBMSbased on IP multicast, UEs shares resources necessary for data packettransmission with each other to receive the same multimedia data.Accordingly, when UEs satisfying a predetermined reference, which usethe MBMS, exist in the same cell, resource efficiency may be increased.The MBMS is not associated with a RRC connection state and thus theRRC_IDLE UE may also receive the MBMS.

A logical channel for the MBMS, that is, a MBMS control Channel (MCCH)or a MEMS traffic channel (MTCH) may be mapped to a transport channel,that is, an MBMS channel (MCH). The MCCH transmits an RRC messageincluding MBMS-related common control information and the MTCH transmitstraffic of a specific MBMS. When one MCCH may exist in every MBMS SingleFrequency Network (MBSFN) area that transmits the same MBMS informationor traffic and a plurality of MBSFN areas are provided by one cell, theUE may receive a plurality of MCCHs. FIG. 7 is a diagram showing atransmission method of MCCH information.

Referring to FIG. 7, when a MBMS-related RRC message is changed in apredetermined MCCH, a PDCCH transmits a MBMS-radio network temporaryidentity (M-RNTI) and an MCCH indicator indicating the MCCH. A UEsupporting the MBMS may receive the M-RNTI and the MCCH indicatorthrough the PDCCH, check that the MBMS-related RRC message is changed inthe MCCH, and receive the MCCH. The MBMS-related RRC message may bechanged in every change cycle and may be repeatedly broadcast in everyrepeat cycle. FIG. 7 is a diagram showing the transmission method of theMCCH information.

The MCCH transmits an MBSFNAreaConfiguration message indicating settingbetween a current MBMS session and an RB corresponding thereto. The MCCHmay receive one or more MBMSs or may transmit an MBMSCountingRequestmessage for counting of the number of RRC_CONNECTED UEs.

In addition, specific MBMS control information may be provided through aBCCH. In particular, the MBMS control information may be included inSystemInformationBlockType13 broadcast through the BCCH.

Hereinafter, a home eNB (HeNB) (or HNB) will be described. A mobilecommunication service may be provided through an eNB owned by anindividual or a specific service provider as well as an eNB of a mobilenetwork operator. Such an eNB is referred to as an HNB or HeNB. Anobject of the HeNB is to basically provide a specialized service of aclosed subscriber group (CSG). However, the HeNB may provide services toother subscribers in addition to the CSG according to operational modesettings of the HeNB.

FIG. 8 is a diagram of a wireless communication system including a HeNB.

Referring to FIG. 8, an E-UTRAN may operate a HeNB gateway (HeNB GW) inorder to provide a service of the HeNB. HeNBs may be connected to an EPCthrough the HeNB GW or may be connected directly to the EPC. The HeNB GWis recognized as a general cell by an MME and is recognized as the MMEby the HeNB. Accordingly, the HeNB and the HeNB GW are connected to eachother through an S1 interface and the HeNB GW and the EPC are alsoconnected to each other through the S1 interface. In addition, when theHeNB and the EPC are connected directly to each other, the S1 interfacemay also be used.

In general, the HeNB has higher radio transmission output power comparedwith an eNB of a mobile network operator. Accordingly, generally, aservice coverage provided by the HeNB is smaller than a service coverageprovided by the eNB. Due to this property, from the viewpoint of theservice coverage, a cell provided by the HeNB is frequently categorizedinto a femto cell compared with a macrocell provided by the eNB. Fromthe viewpoint of a provided service, when the HeNB provides a service toa CSG only, the cell provided by the HeNB is referred to as a CSG cell.

Conventionally, when a UE tries to receive the MBMS, a problem that theUE cannot properly receive the MBMS may arise for the followingreasons. 1) When the UE moves to a CSG cell, the UE cannot receive theMBMS from the CSG cell because the CSG cell does not support the MBMSdue to its property. 2) The UE cannot simultaneously receive the MBMSand other services according to the capabilities of the UE.

Thus, according to the present invention, in order to overcome theproblem that the UE cannot receive the MBMS, the UE prioritizes userpreferences of the MBMS and other services and transmits indicators ofthe user preferences through a wireless network. Here, the servicesexcluding the MBMS may be a unicast service and may include a voiceservice, a UE dedicated service, or a virtual private network (VPN)service. The VPN service refers to a service system that directlycontrols and monitors a communication network in companies.

The user preferences may refer to preferences of the MBMS and a CSGservice (or local IP access (LIPA) service). For example, when thepreference of the CSG service (or LIPA service) is higher than thepreference of the MBMS, the E_UTRAN may move, that is, handover the UEto the CSG cell (or LIPA cell). In addition, when the preference of theCSG service (or LIPA service) is lower than the preference of the MBMS,that is, when the reference of the MBMS is relatively high, the E_UTRANmay handover the UE to a cell providing the MBMS, instead of moving theUE to the CSG cell (or LIPA cell).

FIG. 9 is a diagram of a handover process based on service preference,according to an embodiment of the present invention.

Referring to FIG. 9, first, a UE determines service preference. Forexample, the UE may prefer a CSG service to an MBMS or prefer the CSGservice to the MBMS. The UE may prefer a first MBMS (service) to asecond MBMS (service) or prefer a first MBSFN area to a second MBSFNarea. In addition, the UE may prefer the MBMS to a UE dedicated serviceor prefer the UE dedicated service to the MBMS. After the determinationof the service preference, the UE transmits service preferenceinformation to a CN (or a radio access network (RAN)) in step 901.Preferably, the UE may transmit information about preferred service(s)and preferred MBSFN area(s), that is, MBMS ID(s) or MBSFN area ID(s) inaddition to the service preference information of the UE to the CN.

Then, the CN that receives the service preference information transmitsthe service preference information to a cell connected to the UE, thatis, a serving cell, in step 902. The service preference information maybe sequentially transmitted to the UE, the CN, and the serving cell inthe order stated through a NAS layer. However, alternatively, theservice preference may be transmitted from the UE directly to theserving cell via RRC signaling.

After measurement of one or more target cells, when quality of ameasured target cell is equal to or greater than a preset thresholdvalue, the UE may inform the serving cell of information about thequality of the target cell in step 903. That is, the UE may inform theserving cell of a measurement report message. In this case, the UE maytransmit the measurement report message that contains the target cellquality information together with information about a MBMS receptionstate. The measurement report message is reported to the serving cellthat is a source cell. Here, the MBMS reception state information mayindicate whether the UE currently receives the MBMS provided at afrequency of the target cell or the UE is interested in reception of theMBMS provided at the frequency of the target cell.

Then, the source cell may determine handover according to the servicepreference in addition to the target cell quality information in step904. For example, when the UE prefers the MBMS to the CSG service, thesource cell determines handover to a non-CSG cell instead of a CSG cell.When the UE prefers the CSG service to the MBMS, the source celldetermines handover to the CSG cell instead of the non-CSG cell. Whenthe UE moves to the CSG cell, the UE may stop receiving the MBMS.

When the UE receives or wants to receive the first MBMS and the secondMBMS, if the first MBMS and the second MBMS are provided at differentfrequencies, the source cell determines a cell having a frequency atwhich the preferred MBMS is provided as the target cell and determineshandover to the target cell.

In FIG. 9, for convenience of description, it is assumed that theservice preference indicates that the UE prefers the MBMS to the CSGservice and the source cell determines the non-CSG cell as the targetcell according to the service preference and determines handover to thetarget cell.

Thus, the source cell transmits a handover request message to the targetcell in step 905. The handover request message may include the MBMSreception state information received from the UE. That is, when the UEis interested in the MBMS or receives the MBMS, the MBMS reception stateinformation may include a frequency at which the MBMS is provided, or anID of MBSFN area or MBMS providing the MBMS. Alternatively, the MBMSreception state information may be contained in a handover completionmessage that will be described below and then the UE may transmit thehandover completion message directly to the target cell.

When the target cell is ready to provide the MBMS, the target celltransmits a handover request ACK message to the source cell in step 906,and the source cell transmits a handover command message to the UE instep 907.

The UE that receives the handover command message from the source cellmay receive an MBMS notification transmitted from the target cell usinginformation included in the handover command message in step 908. Indetail, the UE may blind decode a PDCCH masked with an M-RNTI to acquirethe MBMS notification. Here, the MBMS notification refers to informationto indicate session start to the UE and to transmit correspondingresource information and the session start indicates that datatransmission of a corresponding service is prepared.

The UE that acquires the MBMS notification transmits the handovercompletion message in step 909. In addition to a process of, at thesource cell, transmitting the handover request message containing theMBMS reception state information to the target cell, the MBMS receptionstate information may be contained in the handover completion messageand then the UE may transmit the handover completion message directly tothe target cell, as described above.

Lastly, when the MBMS notification indicates information change in theMBSFN area providing the MBMS, the UE receives a MCCH of the MBSFN areato acquire the changed information in step 910. When the MCCH indicatesthe session start of the MBMS, the UE sets a MTCH of the MBMS andreceives MBMS data in step 911.

As described above, according to the present invention, the UE maydetermine the service preferences of the MBMS and other services and maytransmit the indicators indicating the service preferences to the CN soas to smoothly receive the MBMS.

FIG. 10 is a block diagram of a communication apparatus 1000 accordingto an embodiment of the present invention.

Referring to FIG. 10, the communication apparatus 1000 includes aprocessor 1010, a memory 1020, a radio frequency (RF) module 1030, adisplay module 1040, and a user interface module 1050.

The communication apparatus 1000 is shown for convenience of descriptionand some modules thereof may be omitted. In addition, the communicationapparatus 1000 may further include necessary modules. In addition, somemodules of the communication apparatus 1000 may be subdivided. Theprocessor 1010 is configured to perform an operation of the embodimentof the present invention described with reference to the drawings. For adetailed description of the operation of the processor 1010, referencemay be made to the description associated with FIGS. 1 to 9.

The memory 1020 is connected to the processor 1010 so as to store anoperating system, an application, program code, data and the like. TheRF module 1030 is connected to the processor 1010 so as to perform afunction for converting a baseband signal into a radio signal orconverting a radio signal into a baseband signal. To this end, the RFmodule 1030 performs analog conversion, amplification, filtering andfrequency up-conversion or inverse processes thereof. The display module1040 is connected to the processor 1010 so as to display a variety ofinformation. As the display module 1040, although not limited thereto, awell-known device such as a liquid crystal display (LCD), a lightemitting diode (LED), or an organic light emitting diode (OLED) may beused. The user interface module 1050 is connected to the processor 1010and may be configured by a combination of well-known user interfacessuch as a keypad and a touch screen.

The embodiments of the present invention described above arecombinations of elements and features of the present invention. Theelements or features may be considered selective unless otherwisementioned. Each element or feature may be practiced without beingcombined with other elements or features. Further, an embodiment of thepresent invention may be constructed by combining parts of the elementsand/or features. Operation orders described in embodiments of thepresent invention may be rearranged. Some constructions of any oneembodiment may be included in another embodiment and may be replacedwith corresponding constructions of another embodiment. It is obvious tothose skilled in the art that claims that are not explicitly cited ineach other in the appended claims may be presented in combination as anembodiment of the present invention or included as a new claim bysubsequent amendment after the application is filed.

The embodiments of the present invention may be achieved by variousmeans, for example, hardware, firmware, software, or a combinationthereof. In a hardware configuration, an embodiment of the presentinvention may be achieved by one or more ASICs (application specificintegrated circuits), DSPs (digital signal processors), DSDPs (digitalsignal processing devices), PLDs (programmable logic devices), FPGAs(field programmable gate arrays), processors, controllers,microcontrollers, microprocessors, etc.

In a firmware or software configuration, an embodiment of the presentinvention may be implemented in the form of a module, a procedure, afunction, etc. Software code may be stored in a memory unit and executedby a processor. The memory unit is located at the interior or exteriorof the processor and may transmit and receive data to and from theprocessor via various known means.

It will be apparent to those skilled in the art that variousmodifications and variations can be made in the present inventionwithout departing from the spirit or scope of the invention. Thus, it isintended that the present invention cover the modifications andvariations of this invention provided they come within the scope of theappended claims and their equivalents.

INDUSTRIAL APPLICABILITY

Although an example of applying a method and apparatus for transmittingservice preference information from a user equipment (UE) in a wirelesscommunication system to a 3^(rd) generation partnership project (3GPP)long term evolution (LTE) system has been described, the presentinvention is applicable to various wireless communication systems inaddition to the 3GPP LTE system.

1-12. (canceled)
 13. A method of communicating with a network at a user equipment in a wireless communication system, the method comprising: prioritizing a multimedia broadcast multicast service (MBMS) service reception above a non-MBMS service reception; and transmitting an indication indicating that the MBMS reception is prioritized above the non-MBMS service reception to the network.
 14. The method of claim 13, wherein the indication is transmitted with information on the MBMS service preferred by the user equipment.
 15. The method of claim 13, wherein the non-MBMS service is a unicast service.
 16. The method of claim 13, further comprising: receiving system information including information on the MBMS service.
 17. The method of claim 14, further comprising: receiving the MBMS service preferred by the user equipment from the network.
 18. The method of claim 13, wherein the indication is transmitted using a radio resource control (RRC) message.
 19. A method of communicating with a user equipment at a network in a wireless communication system, the method comprising: transmitting system information including information on a multimedia broadcast multicast service (MBMS) service to the user equipment; and receiving an indication indicating that the MBMS service reception is prioritized above a non-MBMS service reception from the user equipment.
 20. The method of claim 19, wherein the indication is received with information on the MBMS service preferred by the user equipment.
 21. The method of claim 19, wherein the non-MBMS service is a unicast service.
 22. The method of claim 20, further comprising: transmitting, to the user equipment, the MBMS service preferred by the user equipment.
 23. The method of claim 19, wherein the indication is received using a radio resource control (RRC) message. 